Several publications and patent documents are cited throughout the specification in order to describe the state of the art to which this invention pertains. Each of these references is incorporated herein as though set forth in full.
Genetic modification of non-humans is useful for the production of genetically superior farm animals. Transgenic animals have been successfully produced via direct somatic cell nuclear transfer into a recipient enucleated oocyte which is then cultured under conditions conducive to blastocyst formation followed by transplantation of the resulting embryo into a surrogate animal. This methodology allows for the production of genetically identical individuals which have superior growth characteristics, e.g., greater milk production, leaner body mass, etc.
Therapeutic cloning methods for the repair of human tissues provides great promise for the treatment of human disease. To date, however such approaches have relied upon the use of human embryos which raises a variety of moral and ethical concerns. These concerns have hampered the progress of the research. It would be highly advantageous if compositions and methods were available for reproducibly generating germ cells from a continuous source of mammalian embryonic stem cells. If such germ cells could then be induced to form oocytes and spermatogonia, such methods would provide a powerful approach for the treatment of infertile couples. Oocytes so obtained could also be genetically transformed and induced to differentiate into desired cell types, for use in the generation of tissues for therapeutic cloning. Such methods would obviate the need for harvesting oocytes and would provide a continuous source for such cells. Additionally, the ethical concerns of harvesting human oocytes would be overcome by such a method.